Scanning Microscope Used for Studying Stimulation of Molecules at Nanoscale

Scientists at UCLA has have isolated two molecules simultaneously on a substrate, controlled the stimulation with UV rays, and recorded their findings both before and after the stimulation.

This is an endeavor to monitor substances at the nanoscale. The paper was published in the March 10 issue of Science.

Paul S Weiss, who leads the team, is the director of UCLA's California NanoSystems Institute (CNSI) and professor of materials science and engineering at the Henry Samueli School of Engineering and Applied Science. This manipulation of molecular reactions is called regioselectivity. The molecules can be isolated and combined for getting various regioselective responses. The theoretical study was led by Kendall Houk, professor of chemistry and biochemistry at UCLA.

Weiss stated that the scanning tunneling microscope can be used to determine molecular light absorption and charge dissipation in solar cells. He further added that manufacturers can enhance these molecules with artificial chemists. A research team led by Professor Alex Jen at the University of Washington collaborated on this project.

Moonhee Kim in Weiss' lab isolated pairs of molecules by developing nanostructures to let only two molecules fit into a single place. In order to isolate and align the molecules in the desired manner, Kim used cutouts, in which certain shapes will only fit. She designed a cutout in a self-assembled monolayer, or SAM on a flat surface of gold. The cutout could hold two molecules that bound with the required alignment. For this, sulfur was applied to the molecule bottoms.

The isolated molecules were then imprisoned on the substrate and simulated with light for initiating a reaction. The team could confirm the alignment and response of the molecules with the microscope designed jointly by Kim and Weiss.

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